SPOautos

That rule is thumb about 1lb/min = 10 is engine HP not rwhp, its also for piston engines not rotary. You can find that formula plastered all kind of hot rod sites, ect. If you look here http://www.hotrod.com/techarticles/e...bo/index2.html over to the right you'll see compressor maps and under them you'll see engine hp potential for pisont engines....they just use the lb/min x 10 rule of thumb.

taking that into consideration if you figured it was 1lb = 10 at the engine, which is only 8.5 at the wheels for a manual, then subtract another 10% for it being a rotary instead of a piston engine you end up with 1lb/min = 7.65 rwhp for a rotary. This would mean that 61lbs/min = 466rwhp and 82lbs/min = 627rwhp which is also what Chris Andersons formula came up with.

Stephen

Wargasm

A-ha! So my formula may not be so good after all... Taking that into account, maybe you need to just bail out entirely on the T72 and go for something a lot bigger if you want to see what the engine will do.... ?

I wish I had this problem Not a bad one to have hehe.

SPOautos

Yea, no kidding I wish I had these problems lol

Marcel Burkett

I woluld up the turbine wheels' size and keep the a/r the same . This would help keep the backpressure down and the HP up and maintain the powerband in the same range.

Jayseven

iTrader: (1)

damn i just cant wait until i can afford a 3 rotor. I am so jealous man. nice car. i would just keep it the same. very impressive numbers man!!!

Red-Rx7

After talking to Justin at Innovative, it looks like I might go with a T76 "R" trim, same exhaust housing. The front compressor cover will be the same, but I will loose a little bit of efficency there. But overall, it should be a pretty big step.

OLD: T72 "Q" Trim, 1.32 AR -- Dual Ball Bearing
NEW: T76 "R" Trim, 1.32 AR -- Dual Ball Bearing

I am kind of nervious now.

FC Alex

R Trim... Is that still considered the highest flowing T4 turbine wheel? Your new turbo will lag more but it will kick your *** from 6k rpm to redline. I can see why you're kind of nervous you're about to jump a good amount of rwhp. Have fun with your new set up man.

I just talked to Justin the other day, because I'm shopping around for a new turbo for my next set up. It is fun to squeeze out 600 rwhp out of daily driven 2 rotor, I just want to see what I can get out of a three rotor. So your new turbo is the GT76 dual ceramic ball bearing, when I go three rotor I'm thinking about going GT80 dual ceramic ball bearing but with an X Trim turbine wheel. I would really appreciate it if you could post new dyno numbers and talk about the response after you get it retuned. Best of luck bro, hope everything works out perfect.

Alex

Red-Rx7

Justin mentioned the GT80 a few times in the conversation, but my main limitation is the fitment of the turbo in the car. The manifold, downpipe, etc has already been designed for this turbo. I don't want to re-engineer everything for a bigger turbo.

So, the T76 will work. The front compressor housing is a little smaller (since I will still use the T72 one) than what is recomended, but it will work.

I am also nervious because the car was awesome before with the throttle response, and horsepower that it made. I mapped out the two compressor maps with the airflow from the dyno rwhp numbers converted to airflow. The first picture, the T72 compressor, are the RPM/RWHP points I pulled from the graph in the following RWHP range:

195rwhp, 300rwhp, 400rwhp, 500rwhp, 560rwhp, 600rwhp, 628.1rwhp.

I applied both airflow values for those rwhp #'s across the board. If I make more rwhp on the T76 map, you could just imagine the blue line extending further right.

T72:



and the T76:

Red-Rx7

Main differences I notice; is that I am in the islands a bunch more for my boost range.

twokrx7

iTrader: (1)

Don't forget to use the actual compressor outlet pressure to do your ratios, at 60+ flowrate there is likely 2+ psi drop from the turbo to your intake manifold pressure sensor. The ratio is likely around 2.1 instead of 1.9 when you read 13.6 psi boost at the motor.

That motor is gonna need more fuel and I suspect you won't be able to put enough tire on the car to drive it on the street at full throttle! 4th gear power slides are in your future!

Red-Rx7

Interesting.. I do not have any hard data to determine what the pressure drop would be.. Is it on average a 2 PSI drop?

I should have the fuel setup:

twokrx7

iTrader: (1)

I have no idea what your pressure drop is, need to measure it if you wanna know.

I'd say you got fuel for a few more hp.

FC Alex

Your fuel is good enough (2 A100's nice)... Just to consider for future projects. My current fuel set up works great. I don't know if you guys know what a surge tank is? But, it acts as a fuel cell keeping the pressure constant. I have a supra fuel pump running into the surge tank which helps keep the fuel pressure constant. The size is between 3 to 5 gallons (guesstimating), I have a aeromotive Tsunami taken the fuel from in 8an steel braided fuel lines. This fuel set up is supposedly good for about 700 to 750 rwhp, without dropping fuel pressure. For a 20B I'm thinking of doing a similiar set up only this time having a 2 supra fuel pumps, a larger surge tank, and 2 Tsunami's which should be enough to reach 1200 rwhp maybe even higher. You guys may not want to use a surge tank set up, because you may not feel secure with it perhaps your not familiar with it. Just thought I toss it out there to are you guys take on it.

Alex

sillbeer

Like this.

maxcooper

Just for basic calculations, though, figuring 2-3 psi is probably in the ballpark. Surely, guesstimating it to be 2 psi would be better than guessing it is 0 psi.

-Max

artguy

my god that dyno vid is intense. sounds so mean....

your car is the envy of all others on this forums. second to none IMHO.

well done.


j

SPOautos

If you want to know what pressure to use on the map just plumb in a nipple on the turbo outlet right before it goes to the IC pipe.

Stephen

Dragon

Is there a write up on your car anywhere.. I'd like to see what size injectors, computer etc you have on the car.. I'm currently running a T76 a/r .96 q trim on my stock ported 20B, but I have a 1.3 ar exaust housing waiting in the trunk of my car for my other 20B side ported engine I built recently... maybe I'll try to go out and have it dyno'd at one of the shops here in the next week to see what it's doing at it's current 15psi boost level.. I know it has enough power that a misshift from second to 5th will tear the counter shaft on the tranny in half..

Red-Rx7

I just got off the phone with Justin from Innovative, and found out the turbo burned itself up. We are rebuilding it with a T76 compressor. Sticking with a Q trim, and all other items.

Red-Rx7

Thanks for all the help in this thread. The final decision has been made:

T76, "Q" trim (due to street driving), 1.32 AR, Dual Ballbearings. The previous turbo burned up inside; and all the ballbearings were toasted.

ITS is now sponsoring my car, so you will definately see some event 1/4 numbers in the close future.

94RHDFD

iTrader: (3)

Good choice Mike, I too have a T76 but with a 1.15 (stock motor) once I get my Microtec install'd and tune we can compare maps

Red-Rx7

Everything is finally coming together for me. I get the new turbo Thursday, and Guru plans to ship out my transmission next week. I will have the Acostas come down most likely the following week, and we will tune the car from 10psi to 14 psi (pump gas), then 14.7 psi to 25psi with race gas.

TechTrix

iTrader: (2)

woah.................. just a quick word of advice, before you put one more mile on your car, rewire the fuel pumps. zip tieing the power wire to a steel braided fuel line is very very bad. steel braided lines are very abrasive and will eventualy rub a hole in your wires shield, and youl be lucky to get out of the car before it burns to the ground. I had a customer with a supra, who got cheap and instead of letting me install his SX fuel pump, did it himself, and zip tied the wire to the braided line. a few months later he was driving down the freeway and his car stalled (the wire burned a hole in the rubber underneath the steel braid and the car dident have enough fuel pressure to continue to run) he pulled over and got out of the car, tried to grab his fire ex. but the whole car was engulfed in flames seconds later. then he stood on the side of the freeway and watched $30,000 of
un-insured car burn to the ground.........

Michael

www.techtrixmotorsports.com

Snook

iTrader: (12)

good call I was thinking the same

and yeah your car is the envy of the forum....I might be up there for a solid 2 rotor but yours just blows it away

yanni

BoostedRex

Red, good luck with that monster!!

To everyone else, thanks for filling this thread with so much useful info! My brain kinda hurts now, but I'm glad that I read all of this. It really helps with my plans!

Zach